FRITZ KISSEL SIEDLUNG
Extension of the listed Fritz Kissel estate with 130 flats in modular timber construction

The Fritz Kissel estate was built in the early 1950s. It follows on from the large Riedhof estate project from the May era, but differs fundamentally from the estates of the 1920s: the short three- and four-storey rows are aligned in a north/south direction and turned slightly towards each other. Vehicular access is from the gable ends of the rows, with residential paths leading through the lush green spaces in between to the house entrances. At the southern edge of the estate, the edge of the city is clearly marked by six-storey point blocks. As Frankfurt’s largest post-war housing estate, it was placed under a preservation order in 2000. Particularly worthy of protection is the urban design, which has remained almost unchanged to this day.

In view of the increasingly scarce living space in Frankfurt, the estate is to be carefully redensified. The following procedure was agreed in close consultation with the heritage authorities:

– Both owners must add storeys together in order to maintain the height development in the estate

– The open spaces could not be built on, all green areas had to be preserved.

– New living space could only be created in the estate by adding storeys, not by building extensions.

– The additions were to be designed in such a way that they differ from the existing buildings in terms of material and color. As a result, the original proportions of the development should remain visible even after the addition of storeys.

– The transoms with the dry floors and the small windows on the top floors were to be retained and not added to.

– All existing buildings were to receive a new coat of paint in the color scheme of the time of construction.

The extension with a total of 130 apartments is made of timber room modules. The blocks will have a single-storey extension, while the point blocks, which were already fitted with elevators during the last refurbishment, will have a two-storey extension. Due to the low weight, low noise emissions and short construction time, as well as for ecological reasons, the extra storeys will be built using modular timber construction. A load distribution level is introduced between the existing building and the extension, which also accommodates the supply lines. This so-called intermediate floor distributes the loads of the extension to the load-bearing transverse bulkheads of the existing building. This means that the floor plans in the extension are independent of the floors below. The result is a mix of two-, three- and four-room apartments with 30% subsidized apartments. The modular structure is no longer recognizable in the later interior spaces. The adaptive timber room modules allow the realization of light-flooded apartments with spacious, flowing and open rooms.

The tenants will remain in their apartments during the construction period. In order to reduce the construction work in the existing building to a minimum, the supply to the additional storeys is via external shafts. Air/water heat pumps powered by photovoltaics will be used to heat the new storeys.

The prefabrication of the room modules takes place in a field factory near Frankfurt. Here, the individual components are delivered on trucks and assembled into a total of 500 room modules on a production line.

A major advantage of a field factory is that it is not the finished modules that are transported across the country, but only the panel material. This enables very effective transportation of the finished room modules from the field factory to the construction site.

It also enables »just in time« delivery of the modules on site for a smooth and fast construction of approx. 100 m² of living space per day.

The entire project took place under full occupancy, had an extremely short and low-noise construction period and is resource-saving both in terms of the building materials used and the subsequent operation of the building.